In the field of signal communication in general, more particularly in the telecommunications field, terminal and isolating modules, which often are configured as strips, are employed to connect and partition subscriber lines and to cross-connect these lines. Such modules are terminated at the one side, designated incoming or fixed side, as well as at the other side, designated outgoing or cross-connect side, with the same amount of pairs in each case. There often is a need to carry out measurements for the connection thus established, for example between the telephone connection of a subscriber and the system engineering of a telecommunications network operator. These measurements serve for example to test the connection in general, or to localize any disturbances which may have occurred.
Also in other technical fields, particularly in the electro-technical field, it is frequently necessary to test or monitor objects. For example, in the field of telecommunications, sometimes it is necessary to obtain test access to the telecommunications line, which runs between the customer or subscriber and the switch or exchange of the telephone company. An extremely high number of these telecommunications lines are distributed between the numerous subscribers and the switch in distribution points. A typical type of distribution point is a main distribution frame in the central office of the telecommunications company. A further example is a network of coaxial cables, which can be used in CATV, for example.
It has hitherto been usual to test a line by plugging a suitable test plug, usually connected to a manual measuring device via test leads, into the particular contacts of a terminal module. In other words, it is required for establishing the connections necessary for testing that someone be present at a distribution point with a manual measuring device.
Generally, the numerous telecommunications lines can be tested by manually connecting a test device with the line to be tested at a point in the line, which is suitable for obtaining test access. However, it is more efficient if a “central” test device is provided. This device can be connected, or connectable with a number of telecommunications lines in a manner to allow test or monitoring access, when this access is desired. For this purpose, so-called star-architectures are known, in which several termination points of the test line can be connected with a test device. For each termination point, a separate line is required.
Furthermore, bus architectures are known, in which a testbus is provided, which is connected with a plurality of termination points by means of a plurality of stub wires, each associated with one termination point. A termination point is that point at which the stub wire is connected or connectable with a line which is to be tested. At the termination point of a particular stub wire, one or more switches are provided in order to allow the desired testing and monitoring. In particular, the arrangement of switches can allow testing in one direction, i.e. towards the subscriber or the switch, in both of the mentioned directions, or it can allow monitoring of the telecommunications line, i.e. the signal transmitted by the telecommunications line is transmitted to the test device without interrupting the line. By means of appropriately controlling the switches at the connection points, a particular line, which is to be tested, can be connected with the test device.
Apart from manual measuring devices, measurements can also be carried out by systems, which are normally used for transmission purposes. Such systems are already provided with corresponding measuring cards and other devices, such as for example a DSLAM mounted on an ADSL or XDSL splitter. For instance, a measuring card can be integrated in the corresponding system. As an alternative, it is possible to terminate an external measuring device and connect it to the system via a corresponding coupling field. Another alternative is to install the corresponding measuring technique on the card. The measurements to be carried out in this case can be “specific to a particular service”, i.e. they are carried out as part of the services rendered by the corresponding system, or they can also be of a general nature for measuring, for example, line interruptions in cases of a failure of the system or the like. These measurements via the system are, however, only possible if this system has already been installed. This means that testing of lines that are not included as a function of the corresponding system is impossible. Thus, it is not possible to test a line as to its functionality prior to the planned installation of a new system.
For example, EP 0 364 658 A2 relates to a distribution point having so-called terminal fields featuring openings into which test plugs can be inserted, among other things. The concerned contacts of the terminal field are tapped by way of suitable contacts at such a test plug, and testing of the line becomes possible due to the connection to a manual measuring device. A similar arrangement is the subject of U.S. Pat. No. 4,629,836.
U.S. Pat. No. 4,208,551 relates to a plug-in card for a line switching system, which can be connected to the switching system and can be extended by a plurality of additional lines.
WO 99/36987 relates to an assembly of telephone connecting strips, which are connected by means of a bus. Switches can be provided in order to connect a selected telecommunications line with a remote control and test device.